The bonus of having an exercise companion means that we get to talk about, well, all the good and bad things about our kids is a given, but we also talk about work, about the economy, about issues in the community, and whether or not the new hairdresser in town is worth going to. When you try to have these discussions with kids around, they get started but come to a quick halt when a child falls on the pavement and needs a Band Aid or when your child says "Excuse me" so many times that you've forgotten what you were talking about anyways.
It's true that exercising with a friend or two requires more planning to match schedules and to arrange for child care, but I'm up for that challenge.